In general, a harness racing sulky comprises a lightweight frame mounted on a pair of wheels, the frame including a pair of shafts which extend forward of the wheels for attachment to a harness worn by the horse. The driver sits on a seat mounted on the frame between the two wheels.
Most sulkies are designed as though they would be operated in a straight line on a flat track. In reality, of course, the race tracks are always banked, and include turns. In addition, the natural gait of a horse includes a lateral (side-to-side) component, even on straight sections of the track. The lateral component is greatest in a turn, where the horse must change the direction of the sulky. These lateral forces, combined with the bank of the track, result in a loss of traction between the sulky wheels and the track, causing the sulky to work against the horse. Ultimately, the driver's lap time is increased, and the horses tend to develop leg joint ailments.
Others have recognized this problem, and have attempted to address it through relatively complicated frame and suspension arrangements, including steerable wheels and compliant joints between the shafts and the other members of the frame. Representative prior art designs are set forth in the Saraydar U.S. Pat. No. 4,817,975, Guarino et al. U.S. Pat. No. 4,863,180, and Acerno et al. U.S. Pat. No. 5,183,279, for example. In general, however, these arrangements tend to be fairly complicated mechanically, and have not enjoyed widespread acceptance in the marketplace.